Modern volume-produced vehicles almost all use a chassis formed of pressed steel. The chassis is formed by a pressing/stamping operation involving one or more steps and spot welding numerous panels to crate the complete body. This produces a steel chassis which has the rigidity necessary for maintaining the dynamic qualities of the vehicle but which is heavy and requires very substantial tooling for its production. The remaining necessary parts of the vehicle structure are then spot-welded or MIG welded to the assembly. Additional exterior body panels and closures can be fixed to the chassis, by bolts, clips or other forms of fixings.
The tools required to form the chassis are physically large, and must therefore be housed in a large facility. A substantial material cost (with attendant environmental footprint) is therefore involved in the chassis, the tools and the facility, the weight of the resulting chassis imposes a substantial ongoing environmental footprint as a result of the consequential energy requirements of the vehicle, and the large facility imposes a corresponding ongoing environmental footprint in terms of its heating, its lighting, its maintenance and so on. The necessary spot-welding involves significant energy consumption. Our earlier application WO2009/122178 therefore set out a novel form of chassis which comprises a tubular metallic framework reinforced with load-bearing composite panels that act to distribute forces across the framework.